JP2015031925A - Lighting device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device which generates white light by using an excitation light source and a phosphor layer.SOLUTION: A lighting device includes: a light source 21; a phosphor layer 32; a polarization separating element 50A placed in an optical path between the light source 21 and the phosphor layer 32; a first retardation plate 26 placed in an optical path between the polarization separating element 50A and the phosphor layer 32; an excitation light reflection part which reflects at least a part of light BLc of a first wavelength band emitted by the first retardation plate 26 in the manner that the light is made incident to the polarization separating element 50A via the first retardation plate 26; a fluorescent light reflection part which reflects fluorescent light YL emitted by the phosphor layer 32 in the manner that it is made incident to the polarization separating element 50A; and a first reflection part 60 which reflects at least a part of light BLs' that progresses from the excitation light reflection part to the light source 21 via the polarization separating element 50A in the manner that the light is made incident to the polarization separating element 50A.

Description

  The present invention relates to a lighting device and a projector.

  2. Description of the Related Art Conventionally, projectors that illuminate a light modulation device with illumination light emitted from an illumination device and enlarge and project image light that is modulated and emitted by the light modulation device onto a screen by a projection optical system are widely known.

  As a light source for a projector, a laser light source such as a semiconductor laser (LD) capable of obtaining light with high luminance and high output has attracted attention. In a projector using a laser light source, excitation light (blue light) emitted from a semiconductor laser and fluorescent light (yellow light) generated by exciting a phosphor with this excitation light are used as illumination light. Has been done. (For example, see Patent Document 1).

JP2012-123179A

  In the light source device described in Patent Document 1, light emitting areas provided with phosphors and non-light emitting areas not provided with phosphors are alternately arranged in the circumferential direction of the rotating fluorescent wheel. According to this, since the fluorescent light (yellow light) emitted from the light emitting area and the excitation light (blue light) reflected from the non-light emitting area are alternately emitted, white light is emitted. It can be seen, but white light is not actually emitted.

  The present invention has been proposed in view of such conventional circumstances, and provides an illumination device that generates white light using an excitation light source and a phosphor layer, and a projector including such an illumination device. The purpose is to do.

  In order to achieve the above object, an illumination device according to the present invention is a second light source that is different from the first wavelength band by being excited by a light source and light of the first wavelength band emitted from the light source. A phosphor layer that generates light in the wavelength band of the light source, and an optical path between the light source and the phosphor layer, and has a polarization separation function for the light in the first wavelength band, and A polarization separation element that transmits or reflects light of two wavelength bands, a first retardation plate disposed in an optical path between the polarization separation element and the phosphor layer, and the first retardation plate An excitation light reflecting portion that reflects at least part of the light in the first wavelength band emitted from the light so as to be incident on the polarization separation element via the first retardation plate, and the phosphor layer The fluorescent light emitted from the phosphor layer is provided on the opposite side of the first retardation plate. Fluorescent light reflecting part that reflects so as to be incident on the polarization separating element, and at least a part of the light traveling from the excitation light reflecting part toward the light source via the polarization separating element to the polarization separating element And a first reflecting portion that reflects so as to be incident.

  According to the configuration of the illuminating device, at least part of the light in the first wavelength band emitted from the first retardation plate toward the phosphor layer is polarized and separated through the first retardation plate. It is reflected by the excitation light reflector so as to enter the element. Further, the light emitted from the phosphor layer is reflected by the fluorescent light reflecting portion. Thereby, illumination light in which light in the first wavelength band and light in the second wavelength band are mixed can be obtained. Further, at least a part of the light traveling from the excitation light reflecting portion to the light source via the polarization separation element is reflected by the first reflection portion so as to enter the polarization separation element. Thereby, since the light reflected by the excitation light reflection part can be reused as illumination light or excitation light, it is possible to improve the utilization efficiency of the light emitted from the light source.

  Moreover, the structure which the light reflected by the said 1st reflection part injects into the said fluorescent substance layer via the said polarization separation element may be sufficient.

  According to this configuration, it is possible to use the light reflected by the first reflecting unit as the excitation light.

  Further, the second phase difference plate provided in the optical path between the first reflection unit and the polarization separation element, and the light reflected by the first reflection unit and travels through the polarization separation element. A second reflection part that reflects light so as to enter the polarization separation element; and a third retardation plate provided in an optical path between the second reflection part and the polarization separation element. In addition, the light reflected by the second reflecting portion may be combined with the light generated in the phosphor layer by the polarization separation element and traveling through the polarization separation element. Good.

  According to this configuration, the light reflected by the second reflecting portion is combined with the light generated in the phosphor layer by the polarization separation element and traveling through the polarization separation element. Therefore, the light reflected by the second reflecting portion can be used as illumination light.

  The first reflection unit may be a mirror provided at a position different from a position through which light in the first wavelength band traveling from the light source to the polarization separation element passes.

  According to this configuration, the first reflecting unit transmits at least a part of the light traveling from the excitation light reflecting unit to the light source via the polarization separation element without blocking the light emitted from the light source. The light can be reflected toward the polarization separation element.

  The first reflection unit may be a mirror having an opening at a position where light of the first wavelength band traveling from the light source to the polarization separation element passes.

  According to this configuration, the first reflecting unit transmits at least a part of the light traveling from the excitation light reflecting unit to the light source via the polarization separation element without blocking the light emitted from the light source. The light can be reflected toward the polarization separation element.

  Further, the fluorescent light reflecting section may function as the excitation light reflecting section.

  According to this configuration, at least a part of the light in the first wavelength band emitted from the first retardation plate toward the phosphor layer is incident on the polarization separation element via the first retardation plate. It is reflected by the fluorescent light reflecting part. Thereby, illumination light in which light in the first wavelength band and light in the second wavelength band are mixed can be obtained.

  Further, the excitation light reflecting portion includes a diffuse reflection surface provided in an optical path between the first retardation plate and the phosphor layer, and the diffuse reflection surface is the first retardation plate. At least part of the light in the first wavelength band emitted from the light is reflected so as to enter the polarization separation element via the first retardation plate, and the other part is reflected on the phosphor layer. You may permeate | transmit toward.

  According to this configuration, at least a part of the light in the first wavelength band emitted from the first retardation plate toward the phosphor layer is incident on the polarization separation element via the first retardation plate. It is reflected by the excitation light reflecting part. Thereby, illumination light in which light in the first wavelength band and light in the second wavelength band are mixed can be obtained. Moreover, the white balance of illumination light can be easily adjusted by adjusting the reflectance with respect to the light of the 1st wavelength band of a diffuse reflection surface.

  The polarization direction of the light in the first wavelength band emitted from the light source reflects the polarization direction of the polarized light transmitted by the polarization separation element and the polarization separation element when entering the polarization separation element. It is preferable to match either one of the polarization directions of the polarized light.

  According to this configuration, the polarization separation element can efficiently reflect or transmit the first light flux toward the fluorescent light emitting element.

  The light source is preferably an array light source in which a plurality of semiconductor lasers are arranged.

  According to this configuration, it is possible to obtain illumination light with higher brightness and higher output.

  Moreover, it is preferable that a collimator optical system is disposed between the light source and the polarization separation element.

  According to this configuration, the first light beam emitted from the light source can be converted into parallel light and incident on the polarization separation element. Therefore, the first light beam can be used efficiently.

  A projector according to the present invention includes an illumination device that irradiates illumination light, a light modulation device that forms image light obtained by modulating the illumination light according to image information, a projection optical system that projects the image light, And any one of the above illumination devices is used as the illumination device.

  According to the configuration of the projector, it is possible to perform bright display with excellent image quality.

It is a top view which shows schematic structure of a projector. It is a top view which shows schematic structure of the illuminating device which is 1st Embodiment. It is a top view which shows each structural example of the light-emitting body layer with which a fluorescence light emitting element is provided. It is a front view which shows the structural example of a 3rd reflection part. It is a top view which shows schematic structure of the illuminating device which is 2nd Embodiment. It is a top view which shows schematic structure of the illuminating device which is 3rd Embodiment. It is a top view which shows schematic structure of the illuminating device which is 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

[projector]
First, an example of the projector 1 shown in FIG. 1 will be described.
FIG. 1 is a plan view showing a schematic configuration of the projector 1.

  The projector 1 is a projection type image display device that displays a color image (image) on a screen (projection surface) SCR. In addition, the projector 1 uses three light modulation devices corresponding to the respective color lights of the red light LR, the green light LG, and the blue light LB. Further, the projector 1 uses a semiconductor laser (laser light source) 21a (not shown in FIG. 1) from which light with high luminance and high output can be obtained as a light source of the illumination device.

  Specifically, as shown in FIG. 1, the projector 1 separates the illumination device 2 that emits illumination light WL and the illumination light WL from the illumination device 2 into red light LR, green light LG, and blue light LB. The color separation optical system 3 and light modulators 4R, 4G, and 4 that modulate the color lights LR, LG, and LB according to image information and form image light corresponding to the color lights LR, LG, and LB. An apparatus 4B, a synthesis optical system 5 that synthesizes image light from each of the light modulation devices 4R, 4G, and 4B, and a projection optical system 6 that projects the image light from the synthesis optical system 5 toward the screen SCR are roughly provided. ing.

  The illuminating device 2 mixes excitation light (blue light) emitted from the semiconductor laser 21a with fluorescent light (yellow light) generated by exciting the phosphor with this excitation light, thereby illuminating light (white light). ) WL is obtained, and a lighting device to which the present invention described later is applied is used. The illumination device 2 irradiates the color separation optical system 3 with the illumination light WL adjusted to have a uniform illuminance distribution.

  The color separation optical system 3 includes a first dichroic mirror 7a and a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, a third total reflection mirror 8c, and a first A relay lens 9a and a second relay lens 9b are roughly provided.

  Among these, the first dichroic mirror 7a has a function of separating the illumination light WL from the illumination device 2 into the red light LR and the other color lights LG and LB, and transmits the separated red light LR. The other color lights LG and LB are reflected. On the other hand, the second dichroic mirror 7b has a function of separating the other color lights LG and LB into the green light LG and the blue light LB, and reflects the separated green light LG and transmits the blue light LB. .

  The first total reflection mirror 8a is disposed in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the light modulation device 4R. On the other hand, the second total reflection mirror 8b and the third total reflection mirror 8c are arranged in the optical path of the blue light LB, and direct the blue light LB transmitted through the second dichroic mirror 7b toward the light modulation device 4B. reflect. Note that it is not necessary to arrange a total reflection mirror in the optical path of the green light LG, and the green light LG is reflected from the second dichroic mirror 7b toward the light modulation device 4G.

  The first relay lens 9a and the first relay lens 9b are disposed downstream of the second total reflection mirror 7b in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b have a function of compensating for the optical loss of the blue light LB due to the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG. doing.

  Each of the light modulation devices 4R, 4G, and 4B includes a liquid crystal panel, and forms image light obtained by modulating the color lights LR, LG, and LB according to image information while passing the color lights LR, LG, and LB. In addition, a pair of polarizing plates (not shown) are arranged on the incident side and the emission side of each of the light modulation devices 4R, 4G, 4B, and a mechanism that allows only linearly polarized light in a specific direction to pass therethrough. It has become.

  Further, on the incident surface side of each of the light modulation devices 4R, 4G, and 4B, a field lens 10R, a field lens 10G, and a field that collimate the respective color lights LR, LG, and LB incident on the light modulation devices 4R, 4G, and 4B. A lens 10B is disposed.

  The combining optical system 5 is composed of a cross dichroic prism. When the image light from each of the light modulation devices 4R, 4G, and 4B is incident, the combining optical system 5 combines the image light corresponding to each color light LR, LG, and LB and combines them. The emitted image light is emitted toward the projection optical system 6.

  The projection optical system 6 includes a projection lens group, and enlarges and projects the image light combined by the combining optical system 5 toward the screen SCR. Thereby, an enlarged color video (image) is displayed on the screen SCR.

[Lighting device]
Next, a specific embodiment of a lighting device to which the present invention is applied used for the lighting device 2 will be described.

(First embodiment)
First, the lighting device 20A shown in FIG. 2 will be described as the first embodiment.
FIG. 2 is a plan view showing a schematic configuration of the illumination device 20A.

  As shown in FIG. 2, the illumination device 20A includes an array light source 21, a collimator optical system 22, an afocal optical system 23, a homogenizer optical system 24, a first reflection unit 60, and a polarization separation element 50A. An optical element 25A, a first retardation plate 26, a pickup optical system 27, a third reflecting portion 32a, a phosphor layer 32, a fourth reflecting portion 32b, an integrator optical system 29, and a polarization A conversion element 30 and a superimposing optical system 31 are roughly provided. In the present invention, the fourth reflecting portion 32b corresponds to a fluorescent light reflecting portion. Further, at least one of the third reflecting portion 32a and the fourth reflecting portion 32b corresponds to the excitation light reflecting portion. When the third reflecting portion 32a is not provided, the fourth reflecting portion 32b is a fluorescent light reflecting portion and an excitation light reflecting portion.

  The array light source 21 has an optical axis ax1. Assuming that the optical axis of the fluorescent light YL emitted from the fluorescent light emitting element 28 is ax2, the optical axis ax1 and the optical axis ax2 are in the same plane and are orthogonal to each other.

  The array light source 21 is composed of a plurality of semiconductor lasers 21a arranged. Specifically, the array light source 21 is configured by arranging a plurality of semiconductor lasers 21a in an array in a plane orthogonal to the optical axis ax1.

  On the optical axis ax1, the array light source 21, the collimator optical system 22, the afocal optical system 23, the homogenizer optical system 24, and the optical element 25A are arranged in this order. On the other hand, on the optical axis ax2, the fourth reflecting portion 32b, the phosphor layer 32, the third reflecting portion 32a, the pickup optical system 27, the first retardation plate 26, the optical element 25A, and the like. The integrator optical system 29, the polarization conversion element 30, and the superimposing optical system 31 are arranged in this order.

  The semiconductor laser 21a emits excitation light (blue light) BL having a peak wavelength in a wavelength region of 440 to 480 nm, for example, as a first light flux in the first wavelength band. The excitation light BL emitted from each semiconductor laser 2a is coherent linearly polarized light, and is emitted in parallel with the optical axis ax1 toward the polarization separation element 50A.

  In the array light source 21, the polarization direction of the excitation light BL emitted from each semiconductor laser 21a is matched with the polarization direction of the polarization component (eg, S polarization component) reflected by the polarization separation element 50A. Then, the excitation light BL emitted from the array light source 21 enters the collimator optical system 22.

  The collimator optical system 22 converts the excitation light BL emitted from the array light source 21 into parallel light, and includes, for example, a plurality of collimator lenses 22a arranged in an array corresponding to each semiconductor laser 21a. . Then, the excitation light BL converted into parallel light by passing through the collimator optical system 22 enters the afocal optical system 23.

  The afocal optical system 23 adjusts the size (spot diameter) of the excitation light BL, and is composed of, for example, two afocal lenses 23a and afocal lenses 23b. Then, the excitation light BL whose size is adjusted by passing through the afocal optical system 23 enters the homogenizer optical system 24.

  The homogenizer optical system 24 converts the light intensity distribution of the excitation light BL into a uniform state (so-called top hat distribution), and includes, for example, a pair of multi-lens array 24a and multi-lens array 24b. Then, the excitation light BL converted to a uniform light intensity distribution by the homogenizer optical system 24 enters the fluorescent light emitting element 28 via the polarization separation element 50A.

  The optical element 25A is formed of, for example, a dichroic prism having wavelength selectivity, and the dichroic prism has an inclined surface K that forms an angle of 45 ° with respect to the optical axis ax1. The inclined surface K forms an angle of 45 ° with respect to the optical axis ax2. Furthermore, the optical element 25A is arranged so that the intersection of the optical axes ax1 and ax2 orthogonal to each other and the optical center of the inclined surface K coincide. The inclined surface K is provided with a polarization separation element 50A having wavelength selectivity.

  The polarization separation element 50A converts the first wavelength band excitation light BL incident on the polarization separation element 50A into an S polarization component (one polarization component) and a P polarization component (the other polarization component) for the polarization separation element 50A. It has a polarization separation function that separates into The polarization separation element 50A reflects the S-polarized component of the excitation light BL and transmits the P-polarized component of the excitation light BL. Further, the polarization separation element 50A has a color separation function for transmitting light having a second wavelength band different from the first wavelength band out of the light incident on the polarization separation element 50A regardless of the polarization state. doing. The optical element 25A is not limited to a prism shape such as a dichroic prism, and a parallel plate dichroic mirror may be used.

  The excitation light BL incident on the polarization separation element 50A is reflected toward the fluorescent light-emitting element 28 as S-polarized excitation light BLs because the polarization direction coincides with the S-polarized light component.

  The first retardation plate 26 is disposed in the optical path between the polarization separation element 50A and the third reflecting portion 32a. As the first retardation plate 26, for example, a ¼ wavelength plate (λ / 4 plate) can be used. The S-polarized (linearly polarized) excitation light BLs incident on the first retardation plate 26 is converted into circularly-polarized excitation light BLc and then incident on the pickup optical system 27.

  The pickup optical system 27 collects the excitation light BLc toward the phosphor layer 32, and includes, for example, a pickup lens 27a and a pickup lens 27b.

  In the optical path between the first retardation plate 26 and the phosphor layer 32, a third reflecting portion 32a is provided. The third reflector 32a diffusely reflects a part of the excitation light BLc incident from the pickup optical system 27 so as to be incident on the polarization separation element 50A via the first retardation plate 26. The other part of the light BLc 2 of the excitation light BLc incident from the pickup optical system 27 is transmitted toward the phosphor layer 32. The third reflecting portion 32a transmits light in the second wavelength band.

  The fluorescent light emitting element 28 includes a phosphor layer 32 and a substrate (base material) 33 that supports the phosphor layer 32. In the fluorescent light emitting element 28, the substrate 33 is disposed on the opposite side of the phosphor layer 32 from the side on which the light BLc2 is incident.

  The phosphor layer 32 includes a phosphor that is excited by absorbing the light BLc2 that is the light in the first wavelength band, and the phosphor excited by the light BLc2 is a second different from the first wavelength band. For example, fluorescent light (yellow light) having a peak wavelength in a wavelength region of 500 to 700 nm is generated as light in the wavelength band of.

  As the phosphor layer 32, it is preferable to use a layer excellent in heat resistance and surface processability. When the phosphor layer 32 is not rotated as in the present embodiment, the cooling effect due to the rotation of the phosphor layer 32 cannot be expected. Therefore, it is necessary to use the phosphor layer 32 that has high heat resistance and is easy to cool. For example, as the phosphor layer 32, a phosphor layer in which phosphor particles are dispersed in an inorganic binder such as alumina, or a phosphor layer in which phosphor particles are sintered without using a binder is preferably used. it can.

  As shown in FIG. 3A, FIG. 3B, and FIG. 3C, a fourth reflecting portion 32b is provided on the side of the phosphor layer 32 opposite to the side on which the light BLc2 is incident. . The fourth reflecting portion 32b is made of a specular reflecting surface. This specular reflection surface can be formed by providing the reflection film 32c on the surface of the phosphor layer 32 opposite to the side on which the light BLc2 is incident. Further, when the substrate 33 has light reflection characteristics, the mirror reflection surface can be formed by mirroring the surface of the substrate 33 that faces the phosphor layer 32.

  The fourth reflecting portion 32b reflects a portion of the fluorescent light YL1 generated in the fluorescent material layer 32 so as to enter the polarization separation element 50A and emits the fluorescent light YL1 to the outside of the fluorescent material layer 32. . Further, the fourth reflecting portion 32 b reflects the component of the light BLc 2 that has not been absorbed by the phosphor layer 32 so as to enter the polarization separation element 50 A via the first retardation plate 26. Of the fluorescent light generated in the fluorescent layer 32, another part of the fluorescent light YL2 is emitted outside the fluorescent layer 32 without passing through the fourth reflecting portion 32b. As described above, the fluorescent light (yellow light) YL (YL1, YL2) generated in the phosphor layer 32 and the components of the light BLc2 that are not absorbed by the phosphor layer 32 cause the third reflector 32a to pass through. The light passes through and enters the pickup optical system 27 together with the light BLc1.

  The fluorescent light (yellow light) YL incident on the pickup optical system 27 further passes through the first retardation plate 26. At this time, since the fluorescent light YL is non-polarized light whose polarization direction is not uniform, after passing through the first retardation plate 26, the fluorescent light YL is incident on the polarization separation element 50A without being polarized. The fluorescent light YL passes through the polarization separation element 50A.

  Since the light BLc1 is light diffusely reflected by the third reflecting portion 32a, the polarization state of the light BLc1 is disturbed by diffuse reflection. Further, the polarization state of the component of the light BLc 2 that has not been absorbed by the phosphor layer 32 is disturbed by the phosphor layer 32. Therefore, the component of the excitation light that has not been absorbed by the phosphor layer 32 and the light BLc 1 behave the same after entering the pickup optical system 27. Therefore, the behavior of the light BLc1 will be described below.

  The light (blue light) BLc1 reflected by the third reflecting portion 32a passes through the pickup optical system 27 and the first retardation plate 26 again. The first retardation plate 26 has a function of converting circularly polarized light into linearly polarized light. However, since the polarization state of the light BLc1 is disturbed, the light BLc1 includes light that is converted into P-polarized blue light BLp and light that is converted into S-polarized blue light BLs'.

  The P-polarized blue light BLp that has passed through the first retardation plate 26 passes through the polarization separation element 50A and is used as illumination light WL. On the other hand, the S-polarized blue light BLs ′ that has passed through the first phase difference plate 26 is reflected by the polarization separation element 50 </ b> A and enters the first reflector 60. The first reflecting unit 60 reflects the incident light so as to enter the polarization separation element 50A. As described above, the first reflection unit 60 is configured so that at least a part of the light traveling toward the array light source 21 from the excitation light reflection unit via the polarization separation element 50A enters the polarization separation element 50A. reflect.

  The 1st reflection part 60 consists of a plurality of mirrors 61, as shown in Drawing 4 (a). The plurality of mirrors 61 are provided at positions different from the positions through which the excitation light BL traveling from the array light source 21 to the polarization separation element 50A passes.

  Thereby, as shown in FIG. 2, the first reflection unit 60 does not block the excitation light BL emitted from the array light source 21, and converts the blue light BLs ′ reflected by the polarization separation element 50 </ b> A into the polarization separation element. It can be reflected efficiently toward 50A.

  Moreover, the 1st reflection part 60 is not restricted to the structure which has arrange | positioned several mirror 61 as shown to Fig.4 (a), As shown in FIG.4 (b), the mirror 62 which has several opening part 62a. It may be a configuration in which is arranged. The mirror 62 has a plurality of openings 62a at positions where the excitation light BL emitted from the array light source 21 passes. Thereby, as shown in FIG. 2, the first reflection unit 60 does not block the excitation light BL emitted from the array light source 21, and converts the blue light BLs ′ reflected by the polarization separation element 50 </ b> A into the polarization separation element. It can be reflected efficiently toward 50A.

  Then, the S-polarized blue light BLs ′ reflected by the first reflector 60 is reflected toward the fluorescent light-emitting element 28 by the polarization separation element 50A. In other words, the S-polarized blue light BLs ′ reflected by the first reflector 60 travels toward the phosphor layer 32 via the polarization separation element 50A. As a result, the S-polarized blue light BLs ′ reflected by the first reflector 60 is used to obtain the illumination light WL together with the S-polarized excitation light BLs reflected by the polarization separation element 50A.

  As described above, in the illumination device 20A, the component that is not absorbed by the phosphor layer 32 in the light BLc2 and the light BLc1 that is reflected by the third reflector 32a are efficiently obtained to obtain the illumination light WL. Can be used. Therefore, it is possible to increase the utilization efficiency of the excitation light BL.

  Here, the 3rd reflection part 32a is demonstrated. In the present embodiment, as shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C, the third reflecting portion 32 a includes the first retardation plate 26 and the phosphor layer 32. It is provided in the optical path between.

  The third reflecting portion 32a is composed of a diffuse reflection surface provided on the surface of the phosphor layer 32 on which the light BLc2 is incident. The third reflecting section 32a has a function of diffusing and reflecting a part of the light BLc1 of the excitation light BLc toward the polarization separation element 50A.

  Specifically, for example, as shown in FIG. 3A, the third reflecting portion 32a can be formed by applying texture processing to the surface of the phosphor layer 32 on which the light BLc2 is incident. In this case, the third reflection unit 32a can diffusely reflect a part of the light BLc1 of the excitation light BLc toward the polarization separation element 50A using backscattering by the roughened surface.

  Moreover, the 3rd reflection part 32a can be formed by giving a dimple process to the surface by which the light BLc2 of the fluorescent substance layer 32 injects as shown, for example in FIG.3 (b). In this case, the third reflecting portion 32a can diffusely reflect a part of the light BLc1 of the excitation light BLc toward the polarization separation element 50A using Fresnel reflection by the surface on which many convex surfaces are formed. .

  Further, the third reflecting portion 32a is not limited to one having a large number of convex surfaces formed by dimple processing. For example, as shown in FIG. 3C, the third reflecting portion 32a has a number of concave surfaces formed by dimple processing, or by dimple processing. A convex surface and a concave surface (not shown) may be formed (uneven surface).

  Furthermore, a surface of the third reflecting portion 32a on the side on which the excitation light BLc is incident may be provided with a reflection enhancing film (not shown). In this case, the ratio of the light BLc1 reflected by the third reflecting part 32a can be increased.

  The color temperature of the illumination light WL can be easily adjusted by adjusting the reflectance of the third reflecting portion 32a with respect to the excitation light BLc. When the third reflecting portion 32a is not used, the color temperature of the illumination light WL can be adjusted by adjusting the density of the phosphor particles in the phosphor layer 32. The smaller the density of the phosphor particles, the more components of the light BLc2 that are not absorbed by the phosphor layer 32.

  In the fluorescent light emitting element 28, as shown in FIG. 2, the phosphor layer 32 is fixed to the substrate 33 by an inorganic adhesive S having a light reflection characteristic provided on the side surface of the phosphor layer 32. In this case, the light leaking from the side surface of the phosphor layer 32 can be reflected into the phosphor layer 32 by the inorganic adhesive S having light reflection characteristics. Thereby, the light extraction efficiency of the fluorescent light generated by the phosphor layer 32 can be increased.

  A heat sink 34 is disposed on the surface of the substrate 33 opposite to the surface that supports the phosphor layer 32. Since the fluorescent light emitting element 28 can dissipate heat through the heat sink 34, the phosphor layer 32 can be prevented from being thermally deteriorated.

  As described above, the illumination light (white light) WL is obtained by mixing the blue light BLp and yellow light YL transmitted through the polarization separation element 50A. The illumination light WL passes through the polarization separation element 50A and then enters the integrator optical system 29. In order to obtain white light (illumination light) WL having a high color temperature, the reflectance of the third reflecting portion 32a with respect to the light BLc1 is preferably 10 to 25%, and preferably 15 to 20%. More preferred.

  The integrator optical system 29 equalizes the luminance distribution (illuminance distribution), and includes a pair of lens arrays 29a and 29b. The pair of lens arrays 29a and 29b is composed of a plurality of lenses arranged in an array. The illumination light WL (blue light BLp and yellow light YL) having a uniform luminance distribution by passing through the integrator optical system 29 enters the polarization conversion element 30.

  The polarization conversion element 30 aligns the polarization direction of the illumination light WL, and is composed of, for example, a combination of a polarization separation film and a retardation plate. In particular, the polarization conversion element 30 converts the non-polarized fluorescent light YL into linearly polarized light that matches the polarization direction of the blue light BLp. Then, the illumination light WL whose polarization direction is aligned by the polarization conversion element 30 enters the superimposing optical system 31.

  The superimposing optical system 31 includes a superimposing lens 31a. Then, each illumination light WL is superimposed by passing through the superimposing lens 31a, the luminance distribution is made uniform, and the axial symmetry around the light axis is enhanced.

  In the lighting device 20A having the above-described configuration, the light (blue light) BLc1 reflected by the third reflecting portion 32a and the fluorescent light (yellow light) emitted from the phosphor layer 32 (fluorescent light emitting element 28). Illumination light (white light) WL mixed with YL can be obtained.

  The disturbance of the polarization state when the excitation light reflected by the third reflection part 32a enters the first phase difference plate 26 is caused by the fact that the excitation light reflected by the fourth reflection part 32b is the first phase difference plate. This is smaller than the disturbance of the polarization state when the light is incident on H.26. Since the first reflector 60 cannot reflect all of the light traveling toward the array light source 21 via the polarization separation element 50A, the first reflection unit 60 is directed toward the array light source 21 via the polarization separation element 50A. It is preferable that the amount of traveling light is small. Therefore, it is preferable that the illuminating device 20C includes the third reflecting portion 32a as the excitation light reflecting portion. However, since the fourth reflection unit 32b also functions as an excitation light reflection unit, the lighting device 20C does not necessarily include the third reflection unit 32a.

  Therefore, when such an illuminating device 20A is applied to the illuminating device 2 included in the projector 1, it is possible to perform bright display with excellent image quality while reducing the size and weight of the illuminating device 2 and the projector 1. It becomes.

(Second Embodiment)
Next, a lighting device 20B shown in FIG. 5 will be described as a second embodiment.
In the following description, portions equivalent to those of the lighting device 20A shown in FIG. 2 are not described and are denoted by the same reference numerals in the drawings.

  In this illuminating device 20B, as shown in FIG. 5, on the optical axis ax1, an optical system including an array light source 21, a collimator optical system 22, an afocal optical system 23, a homogenizer optical system 24, and a polarization separation element 50B. The element 25B, the first retardation plate 26, the pickup optical system 27, the third reflecting portion 32a, the phosphor layer 32, and the fourth reflecting portion 32b are arranged in this order. . On the optical axis ax2, the optical element 25B, the integrator optical system 29, the polarization conversion element 30B, and the superimposing optical system 31 are arranged in this order. Here, the optical axis ax2 is the optical axis of the fluorescent light YL emitted from the optical element 25B.

  The polarization separation element 50B converts the S-polarized light component (one polarization component) and the P polarization component (the other polarization component) of the excitation light BL in the first wavelength band incident on the polarization separation element 50B to the polarization separation element 50B. It has a polarization separation function that separates into The polarization separation element 50B reflects the S-polarized component of the excitation light BL and transmits the P-polarized component of the excitation light BL. In addition, the polarization separation element 50B has a color separation function of reflecting light in the second wavelength band different from the first wavelength band out of the light incident on the polarization separation element 50B regardless of the polarization state. doing.

  In the illumination device 20B, the polarization direction of the excitation light BL emitted from each semiconductor laser 21a included in the array light source 21 is matched with the polarization direction of the polarization component (P polarization component) transmitted by the polarization separation element 50B. The other configurations are basically the same as those of the lighting device 20A shown in FIG.

  In the illumination device 20B having the above-described configuration, the excitation light BL incident on the polarization separation element 50B is transmitted toward the fluorescent light emitting element 28 as P-polarized excitation light BLp.

  Since the light BLc1 is light diffusely reflected by the third reflecting portion 32a, the polarization state of the light BLc1 is disturbed by diffuse reflection. Further, the polarization state of the component of the light BLc 2 that has not been absorbed by the phosphor layer 32 is disturbed by the phosphor layer 32. Therefore, the component of the excitation light that has not been absorbed by the phosphor layer 32 and the light BLc 1 behave the same after entering the pickup optical system 27. Therefore, the behavior of the light BLc1 will be described below.

  The light (blue light) BLc1 diffusely reflected by the third reflecting portion 32a passes through the pickup optical system 27 and then passes through the first retardation plate 26. The first retardation plate 26 has a function of converting circularly polarized light into linearly polarized light. However, since the polarization state of the light BLc1 is disturbed, the light BLc1 is converted into light that is converted into P-polarized blue light BLp ′ by the first phase difference plate 26 and light that is converted into S-polarized light BLs. Including. The S-polarized blue light BLs that has passed through the first retardation plate 26 is reflected toward the integrator optical system 29 by the polarization separation element 50B and used as illumination light WL. On the other hand, the P-polarized blue light BLp ′ that has passed through the first retardation plate 26 passes through the polarization separation element 50 </ b> B toward the array light source 21 and enters the first reflection unit 60. The first reflecting unit 60 reflects the incident light so as to enter the polarization separation element 50A.

  The P-polarized blue light BLp ′ reflected by the first reflector 60 passes through the polarization separation element 50 </ b> B toward the fluorescent light emitting element 28. In other words, the P-polarized blue light BLp ′ reflected by the first reflector 60 travels toward the phosphor layer 32 via the polarization separation element 50A. As a result, the P-polarized blue light BLp ′ reflected by the first reflector 60 is used to obtain the illumination light WL together with the P-polarized excitation light BLp transmitted through the polarization separation element 50B.

  The fluorescent light (yellow light) YL emitted from the phosphor layer 32 (fluorescent light emitting element 28) is reflected toward the integrator optical system 29 by the polarization separation element 50B and used as illumination light WL.

  The polarization conversion element 30B converts the fluorescent light (yellow light) YL into linearly polarized light that matches the polarization direction of the light BLs.

  As described above, in the illuminating device 20B, the efficiency of obtaining the illumination light WL using the component of the light BLc2 that has not been absorbed by the phosphor layer 32 and the light BLc1 reflected by the third reflection unit 32a. Can be used. Therefore, it is possible to increase the utilization efficiency of the excitation light BL.

  Therefore, when such an illuminating device 20B is applied to the illuminating device 2 included in the projector 1, it is possible to perform bright display with excellent image quality while reducing the size and weight of the illuminating device 2 and the projector 1. It becomes.

(Third embodiment)
Next, a lighting device 20C shown in FIG. 6 will be described as a third embodiment.
In the following description, portions equivalent to those of the lighting device 20A shown in FIG. 2 are not described and are denoted by the same reference numerals in the drawings.

  As shown in FIG. 6, in addition to the configuration of the illumination device 20A, the illumination device 20C further includes a second phase difference disposed in the optical path between the first reflection unit 60 and the polarization separation element 50A. The optical path between the plate 63, the second reflecting portion 64 disposed on the opposite side of the second retardation plate 63 with the polarization separating element 50A interposed therebetween, and the second reflecting portion 64 and the polarization separating element 50A And a third retardation plate 65 disposed therein. As the second retardation plate 63, for example, a ¼ wavelength plate can be used. In addition, as the third retardation plate 65, for example, a quarter wavelength plate can be used.

  The configuration of the second retardation plate 63 is such that the excitation light BL emitted from each lens of the multi-lens array 24b does not enter the plurality of phase differences facing the plurality of mirrors 61 shown in FIG. It is preferable that the plate is arranged. Or the 2nd phase difference plate 63 is arrange | positioned facing the mirror 62 shown in FIG.4 (b), and the phase difference plate by which several opening part was provided in the position corresponding to several opening part 62a. It is preferable that Further, the second retardation plate 63 may be configured to be affixed to the light incident surfaces of the plurality of mirrors 61 or 62.

  The second reflection unit 64 reflects the light reflected by the first reflection unit 60 and traveling through the polarization separation element 50A so as to enter the polarization separation element 50A. Further, the third retardation plate 65 may be configured to be affixed to a light incident surface of a mirror that constitutes the second reflection unit 64.

  In the case of this configuration, the S-polarized blue light BLs ′ emitted from the polarization separation element 50 </ b> A is converted into circularly-polarized blue light BLc ′ by the second phase difference plate 63, and then transmitted to the first reflecting unit 60. Incident. Then, the circularly polarized blue light BLc ′ reflected by the first reflection unit 60 is converted again to P-polarized blue light BLp ′ by the second retardation plate 63 and then enters the polarization separation element 50A. .

  The P-polarized blue light BLp ′ that has entered the polarization separation element 50 </ b> A passes through the polarization separation element 50 </ b> A and then enters the third retardation plate 65. The P-polarized blue light BLp ′ incident on the third retardation plate 65 is converted into circularly-polarized blue light BLc ′ and then incident on the second reflecting portion 64. Then, the circularly polarized blue light BLc ′ reflected by the second reflecting portion 64 is again converted into S-polarized blue light BLs ′ by the third phase difference plate 65 and then enters the polarization separation element 50A. .

  Then, the S-polarized blue light BLs ′ incident on the polarization separation element 50A is reflected toward the integrator optical system 29 by the polarization separation element 50A. In this way, the light reflected by the second reflecting portion 64 is combined with the light that is emitted from the fluorescent light emitting element 28 by the polarization separation element 50A and travels via the polarization separation element 50A. Thus, the S-polarized blue light BLs ′ reflected toward the integrator optical system 29 is used as the illumination light WL together with the P-polarized blue light BLp and the yellow light YL transmitted through the polarization separation element 50A.

  As described above, in the illumination device 20C, the S-polarized blue light BLs ′ emitted from the polarization separation element 50A can be reused as the illumination light WL, so that the utilization efficiency of the excitation light BL can be increased.

  Therefore, when such an illuminating device 20C is applied to the illuminating device 2 provided in the projector 1, it is possible to perform bright display with excellent image quality while reducing the size and weight of the illuminating device 2 and the projector 1. It becomes.

(Fourth embodiment)
Next, a lighting device 20D shown in FIG. 7 will be described as a third embodiment.
In the following description, the same parts as those of the lighting device 20B shown in FIG. 5 are not described and the same reference numerals are given in the drawings.

  As shown in FIG. 7, in addition to the configuration of the illumination device 20B, the illumination device 20D further includes a second retardation plate disposed in the optical path between the first reflection unit 60 and the polarization separation element 50B. 63, a second reflecting portion 64 disposed on the opposite side of the integrator optical system 29 across the polarization separating element 50B, and an optical path between the second reflecting portion 64 and the polarization separating element 50B. And a third retardation plate 65.

  The second reflection unit 64 reflects the light reflected by the first reflection unit 60 and traveling through the polarization separation element 50B toward the polarization separation element 50B.

  In the case of this configuration, the P-polarized blue light BLp ′ emitted from the polarization separation element 50 </ b> B is converted into circularly-polarized blue light BLc ′ by the second retardation plate 63, and then is transmitted to the first reflection unit 60. Incident. Then, the circularly polarized blue light BLc ′ reflected by the first reflection unit 60 is converted again into S-polarized blue light BLs ′ by the second retardation plate 63 and then enters the polarization separation element 50B. .

  The S-polarized blue light BLs ′ incident on the polarization separation element 50 </ b> B is reflected by the polarization separation element 50 </ b> B and then enters the third retardation plate 65. The S-polarized blue light BLs ′ incident on the third retardation plate 65 is converted into circularly-polarized blue light BLc ′ and then incident on the second reflecting portion 64. Then, the circularly polarized blue light BLc reflected by the second reflecting portion 64 is converted again to P-polarized blue light BLp ′ by the third phase difference plate 65 and then enters the polarization separation element 50B.

  Then, the P-polarized blue light BLp ′ incident on the polarization separation element 50 </ b> B passes through the polarization separation element 50 </ b> B toward the integrator optical system 29. In this way, the light reflected by the second reflecting portion 64 is combined with the light that is emitted from the fluorescent light emitting element 28 by the polarization separation element 50B and travels via the polarization separation element 50B. Thus, the P-polarized blue light BLp ′ transmitted toward the integrator optical system 29 is used as the illumination light WL together with the S-polarized blue light BLs and the yellow light YL reflected by the polarization separation element 50B.

  As described above, in the illumination device 20D, the P-polarized blue light BLp ′ emitted from the polarization separation element 50B can be reused as the illumination light WL, so that the utilization efficiency of the excitation light BL can be increased.

  Therefore, when such an illuminating device 20D is applied to the illuminating device 2 included in the projector 1, it is possible to perform bright display with excellent image quality while reducing the size and weight of the illuminating device 2 and the projector 1. It becomes.

In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the above-described embodiment, the array light source 21 in which a plurality of semiconductor lasers 21a are arranged is illustrated. However, the light source provided in the illumination devices 20A to 20D is not limited to such a configuration, and is composed of a single light source. May be.

  Further, a light source that emits non-polarized light, such as an LED light source, may be used instead of the semiconductor laser 21a. In this case, by arranging a polarization conversion element having the same configuration as the polarization conversion element 30 on the LED light source side of the first reflection unit 60, the polarization direction of the first light beam when entering the polarization separation element is adjusted. be able to.

  In the above-described embodiment, the projector 1 including the three light modulation devices 4R, 4G, and 4B is exemplified. However, the projector 1 may be applied to a projector that displays a color image (image) with one light modulation device.

  Moreover, although the illuminating devices 20A-20D have a configuration in which the phosphor layer 32 is provided with the third reflecting portion 32a and the fourth reflecting portion 32b, the third reflecting portion 32a and the fourth reflecting portion are provided. It is also possible to provide at least one of the portions 32b separately from the phosphor layer 32. In this case, the third reflecting portion 32 a may be provided in the optical path between the phosphor layer 32 and the first retardation plate 26. On the other hand, the fourth reflecting portion 32b may be provided on the opposite side of the phosphor layer 32 from the side on which the light BLc2 is incident.

  As the third reflecting portion 32a, an increased reflection film made of a dielectric multilayer film may be provided on the surface of the phosphor layer 32. However, the surface of the phosphor layer 32 may be used as it is as the third reflecting portion 32a. .

  DESCRIPTION OF SYMBOLS 1 ... Projector 2 ... Illuminating device 3 ... Color separation optical system 4R, 4G, 4B ... Light modulation device 5 ... Synthesis optical system 6 ... Projection optical system 7a ... 1st dichroic mirror 7b ... 2nd dichroic mirror 8a ... 1st Total reflection mirror 8b ... Second total reflection mirror 8c ... Third total reflection mirror 9a ... First relay lens 9b ... Second relay lens 10R, 10G, 10B ... Field lenses 20A, 20B, 20C, 20D ... Illuminating device 21 ... Array light source 21a ... Semiconductor laser 22 ... Collimator optical system 23 ... Afocal optical system 24 ... Homogenizer optical system 25A, 25B ... Optical element 26 ... First retardation plate 27 ... Pickup optical system 28 ... Fluorescent light emitting element 29 ... Integrator optical system 30 ... Polarization conversion element 31 ... Superimposing optical system 32 ... Fluorescence Layer 32a ... Third reflecting portion 32b ... Fourth reflecting portion 33 ... Substrate (base material) 34 ... Heat sink 50A, 50B ... Polarization separating element 60 ... First reflecting portion 61 ... Multiple mirrors 62 ... Mirror 62a ... Opening Section 63 ... Second retardation plate 64 ... Second reflection section 65 ... Third retardation plate SCR ... Screen WL ... White light (illumination light) LR ... Red light LG ... Green light LB ... Blue light BL ... Excitation Light (blue light) BLs, BLs ′... S-polarized excitation light BLp, BLp ′... P-polarized excitation light BLc, BLc ′... Circularly polarized excitation light BLc1. YL ... Fluorescent light (yellow light) YL1 ... Some light of fluorescent light YL2 ... Some other light of fluorescent light YLs ... S-polarized fluorescent light YLp ... P-polarized fluorescent light

Claims (11)

A light source;
A phosphor layer that generates light of a second wavelength band different from the first wavelength band by being excited by light of the first wavelength band emitted from the light source;
Polarization separation that is disposed in an optical path between the light source and the phosphor layer and has a polarization separation function for light in the first wavelength band and transmits or reflects light in the second wavelength band Elements,
A first retardation plate disposed in an optical path between the polarization separation element and the phosphor layer;
Excitation light reflection that reflects at least part of the light in the first wavelength band emitted from the first retardation plate so as to be incident on the polarization separation element via the first retardation plate. And
A fluorescent light reflecting portion that is provided on the opposite side of the phosphor layer from the first retardation plate and reflects the fluorescent light emitted from the phosphor layer so as to enter the polarization separation element;
A first reflecting section that reflects at least a part of light traveling from the excitation light reflecting section toward the light source via the polarization separating element so as to be incident on the polarization separating element;
A lighting device comprising:   2. The illumination device according to claim 1, wherein the light reflected by the first reflection unit is configured to enter the phosphor layer via the polarization separation element. A second retardation plate provided in an optical path between the first reflection unit and the polarization separation element;
A second reflection unit configured to reflect light reflected by the first reflection unit and traveling through the polarization separation element so as to be incident on the polarization separation element;
A third retardation plate provided in an optical path between the second reflection unit and the polarization separation element;
The light reflected by the second reflecting portion is configured to be synthesized by the polarization separation element with the light generated in the phosphor layer and traveling through the polarization separation element. The lighting device according to claim 1.   The said 1st reflection part is a mirror provided in the position different from the position through which the light of the said 1st wavelength band which progresses from the said light source to the said polarization separation element passes. 4. The illumination device according to any one of 3.   The said 1st reflection part is a mirror which has an opening part in the position through which the light of the said 1st wavelength band which advances to the said polarization splitting element from the said light source passes. The lighting device according to claim 1.   The lighting device according to claim 1, wherein the fluorescent light reflecting unit functions as the excitation light reflecting unit. The excitation light reflection unit includes a diffuse reflection surface provided in an optical path between the first retardation plate and the phosphor layer,
The diffuse reflection surface causes at least a part of the light in the first wavelength band emitted from the first retardation plate to enter the polarization separation element via the first retardation plate. The illuminating device according to claim 1, wherein the illuminating device reflects the light and transmits another part toward the phosphor layer.   The polarization direction of the light in the first wavelength band emitted from the light source is the polarization direction of the polarized light transmitted by the polarization separation element and the polarized light reflected by the polarization separation element when entering the polarization separation element. The illuminating device according to claim 1, wherein the illuminating device matches any one of the polarization directions.   The illumination device according to claim 8, wherein the light source is an array light source in which a plurality of semiconductor lasers are arranged.   The illumination apparatus according to claim 1, wherein a collimator optical system is disposed between the light source and the polarization separation element. An illumination device that emits illumination light;
A light modulation device for forming image light obtained by modulating the illumination light according to image information;
A projection optical system for projecting the image light,
A projector using the lighting device according to claim 1 as the lighting device.

Images